1. Field of the Invention
The present invention relates generally to electronic devices, and more particularly to systems and methods for sensing the temperature of components within digital devices and adjusting the operation of the components to reduce peak temperatures in the device.
2. Related Art
Integrated circuits such as microprocessors are becoming increasingly complex. The circuit components (e.g., transistors, diodes, resistors and the like) that form these devices are, at the same time, becoming increasingly small, so that more and more functions may be performed by a particular integrated circuit. As the number of circuit components and functions grows, the amount of power that is typically consumed by these integrated circuits typically also increases. With the increased power consumption of the circuits, the amount of heat generated within the circuits increases as well. This heat may affect the performance of the devices, and may even cause the devices to fail.
As a result of the dangers presented by the generation of increased amounts of heat in electronic devices, it is often necessary to be able to detect temperatures within these devices. Thermal sensing circuits are therefore incorporated into some devices in order to detect dangerously high temperatures or even measure temperatures within the devices. For example, a thermal sensing circuit can be incorporated into an integrated circuit in order to sense the temperature of the circuit and determine whether the temperature exceeds a predetermined threshold. If the temperature exceeds this threshold, corrective action (e.g., reducing the activity within the circuit or even shutting down the circuit) can be taken in order to reduce the temperature to a safer level.
Conventionally, thermal sensors include an on-chip component, such as a thermally sensitive diode, and an off-chip component that includes circuitry configured to receive a measurement of some characteristic associated with the on-chip component, and to generate a temperature metric based on this measurement. In the case of an on-chip diode, the voltage drop across the diode is determined, and the temperature is computed based upon this voltage drop.
In conventional systems, one or more thermal sensors are used to sense one or more temperatures within the integrated circuit. These temperatures are then typically processed to generate a single temperature metric (e.g., a maximum or an average of the temperatures.) This temperature metric is then used as the basis for decisions to shut down or slow down the integrated circuit to avoid over-temperature conditions. These systems may not work well, however, in many modern integrated circuits that have multiple functional blocks (e.g., multiprocessor devices.) These devices may have different levels of activity in the different functional blocks which cause the temperatures of the functional blocks to vary. Even within each functional block, there may be hot spots at which activity levels and corresponding temperatures may be higher than in surrounding areas. In these devices, thermal management must be based on a worst-case scenario. In other words, if the temperature in any area of the integrated circuit becomes too high, the operation of the device must be scaled back or stopped. Thus, high temperatures at hot spots can cause the entire device to be shut down or operated at a reduced capacity, even the most of the functional blocks are operating well within acceptable temperature limits. These devices may therefore have less than optimal performance.
It would therefore be desirable to provide systems and methods for providing thermal protection in digital devices, where temperatures sensed in selected areas can be reduced by adjusting the manner in which the device is operated.